Vibration actuator and vibration presenting apparatus

ABSTRACT

Provided is a vibration actuator that includes: a fixing part including a coil, and a core around which the coil is wound, the core including both ends projecting from the coil; a movable part disposed adjacent and opposite to the both ends of the core with a gap provided therebetween in a direction crossing with a winding axis of the coil, the movable part including a yoke formed of a magnetic material, the movable part being fixable to an operation contact surface part that is operated by contact; and a plate-shaped elastic part fixed between the movable part and the fixing part, the plate-shaped elastic part including an elastically deformable bellows-shaped part, the plate-shaped elastic part elastically supporting the movable part to be movable with respect to the fixing part in a direction opposite to at least one of the both ends.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is entitled to and claims the benefit of JapanesePatent Application No. 2018-206111, filed on Oct. 31, 2018, thedisclosure of which including the specification, drawings and abstractis incorporated herein by reference in its entirety.

TECHNICAL FIELD

The present invention relates to a vibration actuator and a vibrationpresenting apparatus including the same.

BACKGROUND ART

Conventionally, there is known a configuration where vibration is givento a finger pulp by a vibration actuator when the finger pulp or thelike of a user touches a display screen displayed on a touch panel atthe time of operating the touch panel that is a sensor panel (see PTL 1and PTL 2).

PTL 1 discloses a mobile terminal apparatus having a vibration actuatorattached on a back surface of a touch panel via a vibration transmittingpart. In this vibration actuator, a movable body is disposed inside ahousing fixed to the vibration transmitting part to be reciprocallymovable along a guide shaft disposed vertically with respect to thetouch panel. With this vibration actuator, the movable body is collidedwith the housing in response to an operation to the touch panel to givevibration to the finger pulp that is touching the touch panel via thevibration transmitting part.

Further, PTL 2 discloses a vibration presenting apparatus that givesvibration in response to operations to a touch panel. In this vibrationpresenting apparatus, a voice coil motor for generating vibration, asupport part that is disposed with a vibration panel and compressed by aprescribed force, a damper that gives breaking work on the vibration ofa vibration part, and a spring that gives a compression force to thesupport part and the damper are provided in parallel between a vibrationpanel that is the vibration part presenting vibration and a housing thatsupports the vibration panel.

CITATION LIST Patent Literature

PTL 1

-   Japanese Patent Application Laid-Open No. 2015-070729    PTL 2-   Japanese Patent Application Laid-Open No. 2016-163854

SUMMARY OF INVENTION Technical Problem

Incidentally, for the apparatus giving an operational feeling by usingvibration on an operation contact surface operated by contact such as adisplay screen of a touch panel, the apparatus is desired to be as thinas possible.

In the apparatus with which the movable body is reciprocally moved(vibrated) vertically with respect to the touch panel in response tooperations on the touch panel like the apparatuses of PTLS 1 and 2,stronger vibration can be given to the finger pulp that touches thetouch panel than the apparatus that vibrates the movable body inparallel to the touch panel.

However, PTL 1 requires the shaft and a supporting mechanism of theshaft in order to move the movable body vertically with respect to thetouch panel. Further, it is required in PTL 2 to provide the supportpart, the damper, and the spring between the housing and the vibrationpanel. Therefore, with PTL 1 and PTL 2, it is required to have thicknessfor securing the space for disposing the shaft and the supportingmechanism of the shaft as well as the support part, the damper, and thespring, respectively.

Also, magnets are essential structural components in PTL 1 and PTL 2,and there is a demand for reducing the cost as much as possible byomitting the magnets.

An object of the present invention is to provide a vibration actuatorcapable of giving a preferable operational feeling to users at the timeof operating a touch panel while reducing the thickness and the costeven when attached to the touch panel, and to provide a vibrationpresenting apparatus including the same.

Solution to Problem

In order to achieve the abovementioned objects, a vibration actuator ofthe present invention includes: a fixing part including a coil, and acore around which the coil is wound, the core including both endsprojecting from the coil; a movable part disposed adjacent and oppositeto the both ends of the core with a gap provided therebetween in adirection crossing with a winding axis of the coil, and the movable partincluding a yoke formed of a magnetic material, the movable part beingfixable to an operation contact surface part that is operated bycontact; and a plate-shaped elastic part fixed between the movable partand the fixing part, the plate-shaped elastic part including anelastically deformable bellows-shaped part, the plate-shaped elasticpart elastically supporting the movable part to be movable with respectto the fixing part in a direction opposite to at least one of the bothends of the core.

A vibration presenting apparatus of the present invention includes: thevibration actuator described above; and a touch panel on which thevibration actuator is mounted.

Advantageous Effects of Invention

The present invention is capable of giving a preferable operationalfeeling to the user at the time of operating the touch panel andreducing the thickness even when attached to the touch panel.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a plane-side appearance perspective view of a vibrationactuator according to Embodiment 1 of the present invention;

FIG. 2 is a bottom-surface side appearance perspective view of thevibration actuator according to Embodiment 1 of the present invention;

FIG. 3 is a plan view of the vibration actuator according to Embodiment1 of the present invention;

FIG. 4 is a sectional view taken along line A-A in FIG. 3 ;

FIG. 5 is an exploded perspective view of the vibration actuatoraccording to Embodiment 1 of the present invention;

FIG. 6 is a sectional view illustrating a state where a sensor isprovided to the vibration actuator according to Embodiment 1 of thepresent invention;

FIG. 7 is a sectional view illustrating a state where a sensor isprovided to the vibration actuator according to Embodiment 1 of thepresent invention;

FIG. 8 is a diagram illustrating a magnetic circuit configuration of thevibration actuator according to Embodiment 1 of the present invention;

FIGS. 9A and 9B are diagrams used for describing operations of thevibration actuator according to Embodiment 1 of the present invention;

FIG. 10 is a plane-side appearance perspective view of ModificationExample 1 of the vibration actuator;

FIG. 11 is a bottom-surface side appearance perspective view ofModification Example 1 of the vibration actuator;

FIG. 12 is a sectional view illustrating a configuration of maincomponents of Modification Example 1 of the vibration actuator;

FIG. 13 is an exploded perspective view of Modification Example 1 of thevibration actuator;

FIG. 14 is a plane-side appearance perspective view of ModificationExample 2 of the vibration actuator;

FIG. 15 is a bottom-surface side appearance perspective view ofModification Example 2 of the vibration actuator;

FIG. 16 is an exploded perspective view of Modification Example 2 of thevibration actuator; and

FIGS. 17A and 17B are perspective views of a touch panel apparatusincluding the vibration actuator according to Embodiment 2 of thepresent invention.

DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments of the present invention will be described indetail by referring to the accompanying drawings.

An orthogonal coordinate system (X, Y, Z) is used for describing theembodiments. The same orthogonal coordinate system (X, Y, Z) is usedalso in illustrations of the drawings to be described later.Hereinafter, the width, length, and height of vibration actuator 10 arelengths in X-direction, Y-direction, and Z-direction, respectively. Inaddition, descriptions will be provided assuming that the plus side inthe Z-direction is “upper side” and the minus side in the Z-direction is“lower side”.

Embodiment 1

<Entire Configuration of Vibration Actuator 10>

FIG. 1 is a plane-side appearance perspective view of a vibrationactuator according to Embodiment 1 of the present invention, FIG. 2 is abottom-surface side appearance perspective view of the vibrationactuator according to Embodiment 1 of the present invention, FIG. 3 is aplan view of the vibration actuator according to Embodiment 1 of thepresent invention, FIG. 4 is a sectional view taken along line A-A inFIG. 3 , and FIG. 5 is an exploded perspective view of the vibrationactuator according to Embodiment 1 of the present invention.

Vibration actuator 10 illustrated in FIG. 1 to FIG. 5 achieves avibrating function of an electronic device by being mounted on theelectronic device as a vibration generation source of touch panel 140(see FIG. 17 ) that is an example of an operation contact surface part.

Vibration actuator 10 in Embodiment 1 is mounted on a touch panelapparatus (see FIG. 17 ) of a car navigation system as an electronicdevice and functions as a vibration presenting apparatus that presentsvibration to a user of touch panel 140. Note that touch panel apparatus100 is an example of the vibration presenting apparatus and, inEmbodiment 1, includes touch panel 140 as a panel that can be touched bythe user via hands, fingers, and the like. Touch panel 140 may be apanel having a display function for displaying images and the like theuser can touch or may be a configuration having no display function butsimply having an operation contact surface part that can be operated bytouch of the user.

Vibration actuator 10 according to Embodiment 1 is mounted on touchpanel (operation contact surface part) 140 (see FIG. 17 ) that displaysimages, for example. In this case, vibration actuator 10 is aconfiguration applied to touch panel apparatus 100 that is capable ofallowing the user who touches touch panel 140 to perform intuitiveoperations by transmitting vibration in response to touch operations onthe screen to the user to feel bodily sensations. Note that touch panel140 of touch panel apparatus 100 includes a contact position output partthat receives a touch operation of the user on touch panel 140 andoutputs the contact position thereof.

Vibration actuator 10 is joined with touch panel 140, receives a drivingsignal from a control part (not illustrated), generates and drivesvibration corresponding to the contact position outputted from touchpanel 140 and transmits the vibration to touch panel 140 to directlyvibrate touch panel 140.

That is, vibration actuator 10 receives the operation of the userperformed on touch panel 140, and is driven accordingly.

Vibration actuator 10 includes: fixing part 30 that includes coreassembly 20 formed by winding coil 22 around core 24, and base part 32;movable part 40 that includes magnetic yoke 41; and plate-shaped elasticparts 50 (50-1, 50-2). Plate-shaped elastic parts 50 (50-1, 50-2)elastically support movable part 40 to be movable in vibrating directionwith respect to fixing part 30.

Vibration actuator 10 vibrates yoke 41 of movable part 40 with coreassembly 20. Specifically, movable part 40 is vibrated with theattraction force of energized coil 22 and core 24 excited by energizedcoil 22 as well as the urging force by plate-shaped elastic parts 50(50-1, 50-2).

Vibration actuator 10 is formed in a flat shape having the Z-directionas the thickness direction. Vibration actuator 10 vibrates movable part40 in the Z-direction with respect to fixing part 30, that is, by havingthe thickness direction as the vibrating direction to bring closer oraway one of top and back surfaces spaced apart from each other in thethickness direction of vibration actuator 10 itself with respect to theother surface in the Z-direction. In Embodiment 1, vibration actuator 10moves movable part 40 to −Z-direction by the attraction force of core24, and moves movable part 40 in +Z-direction by the urging force ofplate-shaped elastic parts 50 (50-1, 50-2).

In vibration actuator 10 of Embodiment 1, movable part 40 is elasticallysupported by a plurality of plate-shaped elastic parts 50 (50-1, 50-2)that are disposed along the direction orthogonal to the Z-direction atpoint symmetrical positions with respect to the moving center of movablepart 40. However, the configuration is not limited thereto. Plate-shapedelastic part 50 is fixed between movable part 40 and fixing part 30,includes an elastically deformable bellows-shaped part, and elasticallysupports movable part 40 in a movable manner with respect to fixing part30 in the direction opposing to at least one end out of both ends(magnetic pole parts 242, 244) of core 24. With such configuration, howplate-shaped elastic parts 50 are provided is not an issue. For example,plate-shaped elastic part 50 may elastically support movable part 40with respect to fixing part 30 (core assembly 20) to be movable in thedirection opposing to one end (magnetic pole part 242 or magnetic polepart 244) of core 24. Further, plate-shaped elastic parts 50-1, 50-2 maybe disposed line symmetrically with respect to the center (movingcenter) of movable part 40, and two or more plate-shaped elastic parts50 may be used as well. Each of plate-shaped elastic parts 50-1 and 50-2is fixed to fixing part 30 at one end side and fixed to movable part 40at the other end side to movably support movable part 40 with respect tofixing part 30 in the vibrating direction (Z-direction, and it isup-and-down direction herein).

<Fixing Part 30>

As illustrated in FIG. 5 , fixing part 30 includes: core assembly 20including coil 22 and core 24; and base part 32.

Base part 32 has core assembly 20 fixed thereto, is connected to movablepart 40 via plate-shaped elastic parts 50 (50-1, 50-2), and supportsmovable part 40 to be movable in the vibrating direction. Base part 32is a flat-shape member, and forms the bottom surface of vibrationactuator 10. Base part 32 includes attaching parts 32 a to which one endof each of plate-shaped elastic parts (50-1, 50-2) is fixed to sandwichcore assembly 20. Each of attaching parts 32 a is disposed with a samespace provided from core assembly 20. Note that the space is a space tobe a deforming area of plate-shaped elastic parts 50 (50-1, 50-2).

Attaching part 32 a includes fixing holes 321 for fixing plate-shapedelastic parts 50 (50-1, 50-2) and fixing holes 322 for fixing base part32 to a base material. Fixing holes 322 are provided at both ends ofattaching part 32 a by sandwiching fixing holes 321. Thereby, base part32 is fixed to the base member (for example, back surface plate 120illustrated in FIG. 17 ) in a fully stable manner.

Base part 32 in Embodiment 1 is formed by processing a sheet metal andconfigured such that one side part and the other side part as attachingparts 32 are spaced apart from each other in the width direction withbottom surface part 32 b interposed therebetween. Between attachingparts 32 a, provided is a recessed part having bottom surface part 32 blower in height than that of attaching parts 32 a. Inside the recessedpart, that is, the space on the top surface side of bottom surface part32 b is for securing the elastic deforming area of plate-shaped elasticparts 50 (50-1, 50-2), and for securing a movable area of movable part40 supported by plate-shaped elastic parts 50 (50-1, 50-2).

Bottom surface part 32 b is a rectangular shape, opening part 36 isformed in the center thereof, and core assembly 20 is located insideopening part 36.

Core assembly 20 is fixed while being partially inserted into openingpart 36. Specifically, split body 26 b of bobbin 26 on the lower side ofcore assembly 20 and a lower-side part of coil 22 are inserted insideopening part 36, and core assembly 20 is fixed such that core 24 islocated on bottom surface part 32 b on a side view. Thereby, length(thickness) in the Z-direction becomes decreased compared to aconfiguration where core assembly 20 is attached on bottom surface part32 b. Further, because a part of core assembly 20, that is, a part ofthe bottom surface side herein, is fixed while being fitted into openingpart 36, core assembly 20 is firmly fixed in a state where it is hard tocome off from bottom surface part 32 b.

Opening part 36 is in a shape contoured to the shape of core assembly20. Opening part 36 in Embodiment 1 is formed in a square shape.Thereby, entire vibration actuator 10 can be shaped substantially into asquare shape on a plan view by disposing core assembly 20 and movablepart 40 in the center of vibration actuator 10. Note that opening part36 may be a rectangular shape (including a square shape).

Core assembly 20 vibrates (reciprocal linear motion in the Z-direction)yoke 41 of movable part 40 in cooperation with plate-shaped elasticparts 50 (50-1, 50-2).

Core assembly 20 in Embodiment 1 is formed in a rectangularplate-shaped. Magnetic pole parts 242 and 244 are disposed in both sideportions of the rectangular plate-shaped spaced from each other in thelongitudinal direction. Magnetic pole parts 242, 244 are disposed tooppose to bottom surfaces of attracted surface parts 46, 47 of movablepart 40 with gap G (see FIG. 6 ) provided therebetween in theX-direction, and counter surfaces (counter surface parts) 20 a, 20 b asthe upper surfaces oppose to the bottom surfaces of attracted surfaceparts 46, 47 of yoke 41 in the vibrating direction of movable part 40.

Core assembly 20 in Embodiment 1 is formed in a rectangularplate-shaped, and includes magnetic pole parts 242 and 244 at the bothside portions spaced from each other in the longitudinal direction.Magnetic pole parts 242 and 244 are disposed to oppose to attractedsurface parts 46 and 47 of movable part 40 with gap G providedtherebetween in the Z-direction.

As illustrated in FIG. 1 and FIG. 3 , core assembly 20 is fixed to basepart 32 with a winding axis of coil 22 aligned toward the opposingdirection of spaced attaching parts 32 a in base part 32.

Core assembly 20 in Embodiment 1 is disposed in the center of base part32, specifically in the center of bottom surface part 32 b.

Core assembly 20 is configured by winding coil 22 around circumferenceof core 24 via bobbin 26.

As illustrated in FIG. 4 , core assembly 20 is fixed to bottom surfacepart 32 b such that core 24 is located on the bottom surface overopening part 36 while being in parallel to bottom surface part 32 b.Core assembly 20 is fixed by screw 68 as a fastening member (see FIG. 1, FIG. 3 to FIG. 7 ) in a state where coil 22 and the part (core mainbody 241) to which coil 22 is wound are located within opening part 36of base part 32.

Specifically, core assembly 20 is fixed to bottom surface part 32 b byfastening screw 68 via fixing hole 28 and fastening hole 33 (see FIG. 5) of bottom surface part 32 b in a state where coil 22 is disposed inopening part 36. Core assembly 20 and bottom surface part 32 b arejoined at two points on the axial center of coil 22 by sandwiching coil22 with both side parts of opening part 36 spaced from each other in theX-direction and magnetic pole parts 242, 244 via screws 68.

Coil 22 is a solenoid that is energized and generates a magnetic fieldat the time of driving vibration actuator 10. Coil 22 together with core24 and movable part 40 forms a magnetic circuit (magnetic path) thatattracts and moves movable part 40. Note that power is supplied to coil22 from an external power source via a control part, not illustrated.For example, through supplying a driving signal to the control part, thepower is supplied to coil 22 to drive vibration actuator 10.

Core 24 includes: core main body 241 around which coil 22 is wound; andmagnetic pole parts 242, 244 provided at both ends of core main body 241excited by energizing coil 22.

Core 24 may be in any types of configuration as long as it is aconfiguration having the length with which the both ends can function asmagnetic pole parts 242, 244 when coil 22 is energized. For example,while it is possible to employ a straight-type (I-type) tabular shape,core 24 of Embodiment 1 is formed in an H-type tabular shape on a planview.

When formed as an I-type core, the area of surfaces (gap side surface)on attracted surface parts 46, 47 side opposing to the both ends(magnetic pole parts) of the I-type core with gap (air gap) G providedtherebetween becomes narrower. Thereby, magnetic resistance in themagnetic circuit may be increased, so that the conversion efficiency maybe deteriorated. Further, there may be no space for positioning of thebobbins or may only be a small space in the longitudinal direction ofthe core for attaching the bobbins to the core, so that it is necessaryto provide the space for positioning separately. In the meantime,because core 24 is the H-type, the gap side surface in the both ends ofcore main body 241 can be expanded in the front-and-rear directions(Y-directions) longer than the width of core main body 241 around whichcoil 22 is wound, thereby making it possible to decrease the magneticresistance and improve the efficiency of the magnetic circuit. Further,positioning of coil 22 can be performed by simply fitting bobbins 26between portions of magnetic pole parts 242, 244 extended out from coremain body 241, so that it is unnecessary to separately provide apositioning member of bobbins 26 for core 24.

In core 24, magnetic pole parts 242 and 244 are provided at each of theboth ends of tabular core main body 241 around which coil 22 is wound bybeing projected toward the direction orthogonal to the winding axis ofcoil 22.

Core 24 is of a magnetic material, and formed from a silicon steelsheet, permalloy, ferrite, or the like. Further, core 24 may also bemade of electromagnetic stainless steel, a sintered material, an MIM(metal injection mold) material, a laminated steel sheet, anelectrogalvanized steel sheet (SECC), or the like.

Each of magnetic pole parts 242 and 244 is provided by being projectedin the Y-direction from both opening parts of coil 22.

Magnetic pole parts 242 and 244 are excited by energizing coil 22,attracts and moves yokes 41 of movable part 40 spaced in the vibratingdirection (Z-direction). Specifically, magnetic pole parts 242 and 244attract, by a magnetic flux to be generated, attracted surface parts 46and 47 of movable part 40 counter-disposed via gap G.

Magnetic pole parts 242 and 244 are tabular bodies extended in theY-direction that is the vertical direction with respect to core mainbody 241 extended in the X-direction. Magnetic pole parts 242 and 244are lengthy in the Y-direction, so that the area of counter surfaces 20a and 20 b opposing to yokes 41 are wider than the configuration formedin the both ends of core main body 241.

Magnetic pole parts 242 and 244 have fixing holes 28 formed in thecenter thereof in the Y-direction, and are fixed to base part 32 byscrews 68 inserted into fixing holes 28.

Bobbin 26 is disposed to surround core main body 241 of core 24. Bobbin26 is formed from a resin material, for example. This makes it possibleto secure electrical insulation with other metallic members (forexample, core 24), so that reliability as the electric circuit can beimproved. By using a resin of high fluidity for the resin material,formability can be improved so that the thickness can be decreased whilesecuring the strength of bobbin 26. Through mounting split bodies 26 aand 26 b to sandwich core main body 241, bobbin 26 is formed in acylindrical shape that covers the periphery of core main body 241. Inbobbin 26, a flange is provided to the both ends of the cylindrical bodyto regulate so that coil 22 comes to be located on the outercircumference of core main body 241.

<Movable Part 40>

Movable part 40 is disposed to oppose to core assembly 20 with gap Gprovided therebetween in the direction orthogonal to the vibratingdirection (Z-direction). Movable part 40 is provided to be able toreciprocally vibrate in the vibrating direction with respect to coreassembly 20.

Movable part 40 includes yokes 41, and includes movable-body side fixingparts 54 of plate-shaped elastic parts 50-1 and 50-2 fixed to yokes 41.

Movable part 40 is disposed by being hanged while being spacedsubstantially in parallel and to be movable in the approaching/leavingdirections (Z-directions) with respect to bottom surface part 32 b viaplate-shaped elastic parts 50 (50-1, 50-2).

Yoke 41 is a tabular body made of a magnetic material such aselectromagnetic stainless steel, a sintered material, an MIM (metalinjection mold) material, a laminated steel sheet, an electrogalvanizedsteel sheet (SECC), or the like. Yoke 41 in Embodiment 1 is formed byprocessing an SECC sheet.

Yokes 41 are hanged to oppose to core assembly 20 with gap G (see FIG. 6) provided therebetween in the vibrating direction (Z-direction) byplate-shaped elastic parts 50 (50-1, 50-2) fixed to respective attractedsurface parts 46 and 47 spaced from each other in the X-direction.

Yoke 41 includes: surface-part fixing part 44 to which an operationcontact surface part (see touch panel 140 illustrated in FIG. 17 ) isattached; and attracted surface parts 46 and 47 counter-disposed withrespect to magnetic pole parts 242 and 244.

Yoke 41 in Embodiment 1 includes opening part (fixing-part side openingpart) 48 in the center thereof. Yoke 41 has a rectangular frame shape.Yoke 41 is formed in a frame shape that surrounds opening part 48 withsurface-part fixing part 44 and attracted surface parts 46, 47.

Opening part 48 opposes to coil 22. In Embodiment 1, opening part 48 islocated right above coil 22, and the opening shape of opening part 48 isformed in a shape to which coil 22 part of core assembly 20 can beinserted when yoke 41 moves to bottom surface part 32 b side.

By configuring yoke 41 to have opening part 48, the thickness of theentire vibration actuator can be decreased compared to a case having noopening part 48.

Further, core assembly 20 is located within opening part 48, so thatyoke 41 is not disposed in the vicinity of coil 22. Therefore, it ispossible to suppress deterioration in the conversion efficiency due tothe magnetic flux leaked from coil 22, so that high output can beachieved.

Surface-part fixing part 44 includes fixing surface 44 a that comes insurface-contact to fix touch panel 140 as an example of the operationcontact surface part. Fixing surface 44 a forms a trapezoid shape on aplan view, and surface-contacts with touch panel 140 that is fixed tosurface-part fixing part 44 via fastening member such as a screwinserted into surface-part fixing hole 42.

Attracted surface parts 46, 47 are attracted to magnetized magnetic poleparts 242, 244 in core assembly 20, and plate-shaped elastic parts 50(50-1, 50-2) are fixed thereto.

Movable-body side fixing parts 54 of plate-shaped elastic parts 50-1 and50-2 are fixed by being laminated, respectively, on attracted surfaceparts 46 and 47. Attracted surface parts 46 and 47 are provided withnotches 49 functioning as clearance of the heads of screws 64 of coreassembly 20 when moved to bottom surface part 32 b side.

Thereby, even when movable part 40 moves to bottom surface part 32 bside and attracted surface parts 46, 47 approach magnetic pole parts242, 244, magnetic pole parts 242, 244 are not to be in contact withscrews 68 that fix magnetic pole parts 242, 244 to bottom surface part32 b, so that a movable area of yoke 41 in the Z-direction can besecured for that.

<Plate-Shaped Elastic Parts 50 (50-1, 50-2)>

Plate-shaped elastic parts 50 (50-1, 50-2) support movable part 40 to bemovable with respect to fixing part 30. Plate-shaped elastic parts 50(50-1, 50-2) support the upper surface of movable part 40 to be the sameheight as that of the upper surface of fixing part 30 or to be on alower surface side than the upper surface of fixing part 30 (uppersurface of core assembly 20 in Embodiment 1) to be in parallel to eachother. Note that plate-shaped elastic parts 50-1, 50-2 have symmetricalshapes with respect to the center of movable part 40 and, in Embodiment1, are members formed in the same manner.

Plate-shaped elastic parts 50 are disposed such that yoke 41 issubstantially in parallel to oppose to magnetic pole parts 242, 244 ofcore 24 of fixing part 30 with gap G provided therebetween. Plate-shapedelastic parts 50 support the lower surface of movable part 40 to bemovable in the vibrating direction at a position closer to bottomsurface part 32 b side than the level substantially the same as theheight level of the upper surface of core assembly 20.

Plate-shaped elastic part 50 is a plate spring including fixing-bodyside fixing part 52, movable-body side fixing part 54, and bellows-likeelastic arm part 56 that communicates fixing-body side fixing part 52with movable-body side fixing part 54.

Plate-shaped elastic parts 50 attaches movable part 40 while attachingfixing-body side fixing part 52 to the top surface of attaching part 32a, attaching movable-body side fixing part 54 to the top surface ofattracted surface parts 46, 47 of yoke 41, and having bellows-likeelastic arm part 56 in parallel to bottom surface part 32 b.

Fixing-body side fixing part 52 surface-contacts with attaching part 32a by being joined and fixed by screws 62, and movable-body side fixingpart 54 surface-contacts with attracted surface parts 46, 47 by beingjoined and fixed by screws 64.

Bellows-like elastic arm part 56 is an arm part having a bellows-shapedpart. By having the bellows-shaped part, bellows-like elastic arm part56 secures the length that allows deformation required for vibration ofmovable part 40 between fixing-body side fixing part 52 and movable-bodyside fixing part 54 and also on the surface orthogonal to the vibratingdirection (surface formed in the X-direction and the Y-direction).

Bellows-like elastic arm part 56 in Embodiment 1 extends in the opposingdirection of fixing-body side fixing part 52 and movable-body sidefixing part 54 and folds back, and the ends that are joined,respectively, to fixing-body side fixing part 52 and movable-body sidefixing part 54 are formed at positions shifted in the Y-direction.

Bellows-like elastic arm parts 56 are disposed at point-symmetrical orline-symmetrical positions with respect to the center of movable part40.

Thereby, movable part 40 is supported from both sides by bellows-likeelastic arm parts 56 having bellows-shaped springs, so that it ispossible to disperse the stress at the time of elastic deformation. Thatis, plate-shaped elastic parts 50 can move movable part 40 in thevibrating direction (Z-direction) without tilting with respect to coreassembly 20, thereby making it possible to improve reliability of thevibrating state.

Each of plate-shaped elastic parts 50 includes at least two or morebellows-like elastic arm parts 56. Thereby, compared to a case wherethere is only one each of bellows-like elastic arm part 56, it ispossible to improve the reliability of the vibrating state by dispersingthe stress at the time of elastic deformation and to improve thestability because the support for movable part 40 can be well-balanced.

The plate spring as plate-shaped elastic part 50 in Embodiment 1 isformed from a magnetic material. Further, movable-body side fixing parts54 of plate-shaped elastic parts 50 are disposed at positions opposingto both ends (magnetic pole parts 242, 244) of core 24 in the coilwinding axis direction or on the upper side thereof and function as amagnetic path. In Embodiment 1, movable-body side fixing parts 54 arefixed by being laminated on the upper side of attracted surface parts 46and 47. This makes it possible to increase thickness H (see FIG. 6 ) ofattracted surface parts 46 and 47 opposing to magnetic pole parts 242,244 of core assembly 20 as the thickness of the magnetic material. Thethickness of plate-shaped elastic parts 50 and the thickness of yoke 41are the same, so that the cross sectional area of the magnetic materialportion opposing to magnetic pole parts 242, 244 can be doubled. Thismakes it possible to expand the magnetic circuit, to ease thedeterioration in the property of the magnetic circuit due to magneticsaturation, and to improve the output compared to a case where the platespring is nonmagnetic.

Note that vibration actuator 10 of Embodiment 1 may be provided with adetection part that detects push-in amount of movable part 40 when theoperation surface part fixed by surface-part fixing part 44 is operated.

For example, as illustrated in FIG. 6 , strain detection sensor 70 thatdetects strain of plate-shaped elastic parts 50 may be provided as adetection part.

Strain detection sensor 70 detects strain of plate-shaped elastic parts50 that are deformed when surface-part fixing part 44 is pushed intobottom surface part 32 b side. Detected strain is outputted to thecontrol part and the like, coil 22 is energized to attract and move yoke41 such that movable part 40 moves in an amount corresponding to thestrain.

Embodiment 1 can function without determining the moving amount of theoperation contact surface part to be operated, as long as contact to theoperation contact surface part can be detected. Further, a more naturalsense of touch can be expressed when the push-in amount with respect toplate-shaped elastic parts 50 can be detected with the moving amountcorresponding to the actual moving amount on the operation contactsurface part.

Strain detection sensor 70 is attached between heads of screws 62 and 64on bellows-like elastic arm parts 56 of plate-shaped elastic parts 50,and disposed in the so-called dead space that is an area not obstructingother members.

Further, as illustrated in FIG. 7 , it is also possible to dispose thedetection part for detecting push-in in a lower part of plate-shapedelastic parts 50 as the dead space. In that case, the detection sensoris electrostatic capacitance sensor 80 for detecting the push-in amountand disposed on bottom surface part 32 b opposing to plate-shapedelastic parts 50. The distance with respect to plate-shaped elasticparts 50 displaced by being pushed in is measured. Thereby, the distancewhen deformed by following the push-in on the operation contact surfacepart can be measured. With such method using the electrostaticcapacitance, it is possible to detect fluctuation in plate-shapedelastic parts 50 or movable part 40 on the lower side of plate-shapedelastic parts 50. In addition, it is also possible to achieve detectionof the push-in amount of the operation contact surface part and togenerate vibration of movable part 40 by corresponding to the push-inamount while maintaining the external dimension of vibration actuator10.

FIG. 8 is a diagram illustrating the magnetic circuit of vibrationactuator 10. Note that FIG. 8 is a perspective view of vibrationactuator 10 cut along line A-A of FIG. 3 and, in the magnetic circuit,there are also magnetic flux flows M similar to the illustration thereofexisting in the part having no such illustration. Further, FIG. 9 aresectional views schematically illustrating move of movable part 40caused by the magnetic circuit. FIG. 9A is a diagram illustrating astate where movable part 40 is held by plate-shaped elastic parts 50 ata position spaced from core assembly 20, and FIG. 9B illustrates movablepart 40 attracted and moved toward core assembly 20 side by a magnetomotive force generated by the magnetic circuit.

Specifically, when coil 22 is energized, core 24 is excited and amagnetic field is generated, thereby forming magnetic poles in both endsof core 24. For example, as illustrated in FIG. 8 , in core 24, magneticpole part 242 is the N-pole, and magnetic pole part 244 is the S-pole.Thereby, the magnetic circuit indicated by magnetic flux flow M isformed between core assembly 20 and yoke 41. Magnetic flux flow M in themagnetic circuit flows to attracted surface part 46 of opposing yoke 41from magnetic pole part 242, passes through surface-part fixing part 44of yoke 41, and reaches magnetic pole part 244 opposing to attractedsurface part 47 from attracted surface part 47. In Embodiment 1,plate-shaped elastic parts 50 are also of magnetic materials. Thereby,the magnetic flux (illustrated as magnetic flux flow M) flown toattracted surface part 46 passes through attracted surface part 46 ofyoke 41 and movable-body side fixing part 54 of plate-shaped elasticparts 50-1, reaching attracted surface part 47 and both ends ofmovable-body side fixing part 54 of plate-shaped elastic part 50-2 viasurface-part fixing part 44 from both ends of attracted surface part 46.

Thereby, according to the principle of electromagnetic solenoid,magnetic pole parts 242, 244 of core assembly 20 generate attractionforce F for attracting attracted surface parts 46, 47 of yoke 41.Thereupon, attracted surface parts 46, 47 of yoke 41 are attracted toboth of magnetic pole parts 242, 244 of core assembly 20, coil 22 isinserted into opening part 48 of yoke 41, and movable part 40 includingyoke 41 moves in F-direction against the urging force of plate-shapedelastic parts 50 (see FIG. 9A and FIG. 9B).

In the meantime, when energization to coil 22 is stopped, the magneticfield disappears, attraction force F of core assembly 20 for movablepart 40 is lost, and movable part 40 is moved back to the originalposition (moved to −F-direction) by the urging force of plate-shapedelastic parts 50.

By repeating such action described above, in vibration actuator 10,movable part 40 reciprocally moves and generates vibration in thevibrating direction (Z-direction).

In vibration actuator 10, it is possible to increase the efficiency ofthe magnetic circuit and achieve high output by disposing attractedsurface parts 46, 47 of yoke 41 adjacent to magnetic pole parts 242, 244of core assembly 20. Further, vibration actuator 10 uses no magnet, sothat a low-cost configuration can be achieved. The bellows-shapedsprings that are plate-shaped elastic parts 50 (50-1, 50-2) enabledispersion of the stress, so that the reliability can be improved.Especially, because movable part 40 is supported by a plurality ofplate-shaped elastic parts 50 (50-1, 50-2), more effective dispersion ofthe stress is possible. As described, vibration actuator 10 is capableof providing a more direct sense of touch by the drive of up-and-downdirection.

By fixing core 24 around which coil 22 is wound and core assembly 20 tofixing part 30, movable part 40 is supported to be movable. Thereby, itbecomes unnecessary to provide a magnetic generating part in theZ-direction, and design becomes simple because the supporting structureis simple. Thus, space can be saved, so that it is possible to decreasethe thickness of vibration actuator 10.

Hereinafter, the driving principle of vibration actuator 10 will simplybe described. Note that it is the same for vibration actuators 10A, 10Bof Modification Examples 1, 2 to be described later, and vibrationactuators 10, 10A, 10B can be driven by generating a resonancephenomenon with a pulse by using following motion equation and circuitequation. The actions are not resonance driven but for expressingoperational feeling of mechanical switches displayed on the operationcontact surface part, and it is also possible to drive the vibrationactuator by generating any types of vibration without using a shortpulse while the vibration actuator in Embodiment 1 is driven byinputting a short pulse via a control part, not illustrated. Examples ofthe mechanical switch may be a tactile switch, alternate-type switch, amomentary switch, a toggle switch, a slide switch, a rotary switch, aDIP switch, and a rocker switch.

Note that movable part 40 in vibration actuator 10 performs reciprocalmotions based on Expressions (1) and (2).

$\begin{matrix}\left\lbrack {{Expression}1} \right\rbrack & \end{matrix}$ $\begin{matrix}{{{m\frac{d^{2}{x(t)}}{{dt}^{2}}} = {{K_{f}{i(t)}} - {K_{sp}{x(t)}} - {D\frac{{dx}(t)}{dt}}}}{m:{{Mass}\lbrack{kg}\rbrack}}{{x(t)}:{{Displacement}\lbrack m\rbrack}}{K_{f}:{Thrust}{{constant}\left\lbrack {N/A} \right\rbrack}}{{i(t)}:{{Current}\lbrack A\rbrack}}{K_{sp}:{Spring}{{constant}\left\lbrack {N/m} \right\rbrack}}{D:{Damping}{{coefficient}\left\lbrack {N/\left( {m/s} \right)} \right\rbrack}}} & (1)\end{matrix}$

$\begin{matrix}\left\lbrack {{Expression}2} \right\rbrack & \end{matrix}$ $\begin{matrix}{{{e(t)} = {{{Ri}(t)} + {L\frac{{di}(t)}{dt}} + {K_{e}\frac{{dx}(t)}{dt}}}}{{e(t)}:{{Voltage}\lbrack V\rbrack}}{R:{{Resistance}\lbrack\Omega\rbrack}}{L:{{Inductance}\lbrack H\rbrack}}{K_{e}:{Counter}{electromotive}{force}{{constant}\left\lbrack {V\left( {{rad}/s} \right)} \right\rbrack}}} & (2)\end{matrix}$

That is, mass “m” [kg], displacement “x(t)” [m], thrust constant “K_(f)”[N/A], current “i(t)” [A], spring constant “K_(sp)” [N/m], and dampingcoefficient “D” [N/(m/s)] in vibration actuator 10 can be changed asappropriate within the range satisfying Expression (1). Also, voltage“e(t)” [V], resistance “R” [Ω], inductance “L” [H], and counterelectromotive force constant “K_(e)” [V/(rad/s)] can be changed asappropriate within the range satisfying Expression (2).

As described, the drive of vibration actuator 10 is determined based onmass “m” of movable part 40, and spring constant K_(sp) of metal springsas plate-shaped elastic parts 50 (elastic bodies; plate springs inEmbodiment 1).

Further, in vibration actuator 10, screws 62 and 64 are used for fixingbase part 32 and plate-shaped elastic parts 50 and for fixingplate-shaped elastic parts 50 and movable part 40. Thereby, plate-shapedelastic parts 50 required to be firmly fixed to fixing part 30 andmovable part 40 for allowing movable part 40 to drive can be firmlyfixed mechanically in a state capable of reworking.

Vibration actuator 10 includes fixing part 30 that includes: coil 22;and core 24 around which coil 22 is wound and both ends thereof areprojected from coil 22. Further, vibration actuator 10 includes movablepart 40 that: includes yokes 41, 41A formed from a magnetic material anddisposed adjacently opposite to counter surfaces 20 a, 20 b of magneticpole parts 242, 244 as the both ends of core 24 with gap G providedtherebetween in the direction crossing with the winding axis of coil 22;and is capable of being fixed to the operation contact surface part thatis operated by contact. Vibration actuator 10 includes plate-shapedelastic parts 50 that: are fixed between movable part 40 and fixing part30; and include bellows-like elastic arm parts 56 that are elasticallydeformed to elastically support movable part 40 with respect to fixingpart 30 to be movable in the direction opposing to magnetic pole parts242, 244. While it is preferable that a plurality of plate-shapedelastic parts 50 be fixed at symmetrical positions with respect to thecenter of movable part 40, movable part 40 may also be support by oneplate-shaped elastic part 50 to be vibratable with respect to fixingpart 30 as described above. Plate-shaped elastic part 50 may include atleast two or more arm parts that connect movable part 40 and fixing part30, and include bellows-like elastic arm part 56. Plate-shaped elasticpart 50 may be made of a magnetic material. In that case, each ofmovable-body side fixing parts (movable-body side attachment parts) 54of plate-shaped elastic parts 50 is disposed in the winding axisdirection of coil 22 or the direction orthogonal to the winding axisdirection with respect to the both ends of core 24, and forms a magneticpath together with core 24 when coil 22 is energized.

Thereby, even when attached to a touch panel that is the operationcontact surface part, it is possible to give a preferable operationalfeeling to the user at the time of operating the touch panel whileachieving reduction in the thickness and the cost.

Modification Example 1

FIG. 10 is a plane-side appearance perspective view of ModificationExample 1 of the vibration actuator, and FIG. 11 is a bottom-surfaceside appearance perspective view of Modification Example 1 of thevibration actuator. FIG. 12 is a sectional view illustrating aconfiguration of main components of Modification Example 1 of thevibration actuator, and FIG. 13 is an exploded perspective view ofModification Example 1 of the vibration actuator.

In vibration actuator 10A illustrated in FIG. 10 to FIG. 13 , screws 62,64, and 68 used in the configuration of vibration actuator 10 for fixingbase part 32 and plate-shaped elastic parts 50 and for fixingplate-shaped elastic parts 50 and movable part 40, respectively, arechanged. Specifically, vibration actuator 10A is configured by usingrivets 92, 94, and 98 instead of screws 62, 64, and 68. Each of rivets92, 94, and 98 is formed with a head and a body without a threaded part,which is inserted into a bored member, and an end on the opposite sideis riveted and plastically deformed to join the bored members with eachother. The riveting may be performed by a pressing machine or a specialtool, for example.

Rivets 92 fix attaching part 32 a of fixing part 30 and plate-shapedelastic parts 50, and rivets 94 fix plate-shaped elastic parts 50 andyoke 41. Further, rivets 98 fix fixing part 30 to bottom surface part 32b in a state where coil 22 of core assembly 20 is disposed in fasteninghole 33 of bottom surface part 32 b. Thereby, plate-shaped elastic parts50 can be more firmly fixed than the case of using screw 62, 64, and 68,so that plate-shaped elastic parts 50 can be stably fixed to fixing part30 and movable part 40.

Modification Example 2

FIG. 14 is a plane-side appearance perspective view of ModificationExample 2 of the vibration actuator, FIG. 15 is a bottom-surface sideappearance perspective view of Modification Example 2 of the vibrationactuator, and FIG. 16 is an exploded perspective view of ModificationExample 2 of the vibration actuator.

Vibration actuator 10B of Modification Example 2 includes movable yoke40A that is a single member formed by integrating plate-shaped elasticparts 50 and yoke 41 in the configuration of vibration actuator 10.Vibration actuator 10B includes: fixing part 30 in the configuration ofvibration actuator 10; and movable yoke 40A that is movable with respectto fixing part 30.

Movable yoke 40A includes: yoke 41A having the same function as that ofyoke 41; and plate-shaped elastic parts 450-1, 450-2 having the samefunction as that of plate-shaped elastic parts 50 (50-1, 50-2).

Yoke 41A is formed by integrating attracted surface parts 46, 47 of yoke41 and movable-body side fixing parts 54 of plate-shaped elastic parts50-1, 50-2 into a single member.

In movable yoke 40A, yoke 41A forms a frame shape surrounding openingpart 48 (see FIG. 16 ) with surface-part fixing part 44 and attractedsurface parts 46A, 47A, and plate-shaped elastic parts 450-1, 450-2 areprovided to be projected toward the X-direction from attracted surfaceparts 46A, 47A, respectively.

Each of plate-shaped elastic parts 450-1 and 450-2 includes: fixing-bodyside fixing part 452 having the same function as that of fixing-bodyside fixing part 52 of plate-shaped elastic part 50; and bellows-likeelastic arm part 456 having the same function as that of bellows-likeelastic arm part 56.

With such configuration, yoke 41A and plate-shaped elastic part 450 canbe in a same height level with respect to bottom surface part 32 b offixing part 30, so that the thickness (height in the Z-direction) ofvibration actuator 10B itself can be reduced for that.

Further, the number of components can be decreased compared to that ofvibration actuator 10, so that manufacturing steps can be decreased.

Embodiment 2

FIGS. 17A and 17B are perspective views of a touch panel apparatusincluding vibration actuator 10 according to Embodiment 2 of the presentinvention.

FIGS. 17A and 17B are perspective views of touch panel apparatus 100including vibration actuator 10 according to Embodiment 2 of the presentinvention. FIG. 17A is a perspective view of touch panel apparatus 100including vibration actuator 110 according to Embodiment 2 of thepresent invention, and FIG. 17B is a right side view of the sameapparatus. Touch panel apparatus 100 illustrated in FIG. 17 is anexample of a vibration presenting apparatus. Vibration actuator 110 isvibration actuator 10, and it is fixed to back surface plate 120 oftouch panel 140 that displays images via connection pillar part 160.Further, while vibration actuator 10 is used as vibration actuator 110,vibration actuator 110 is not limited thereto but may also be vibrationactuator 10A or vibration actuator 10B.

In touch panel apparatus 100 including touch panel 140, touch panel 140is fixed to movable part 40 of vibration actuator 110 having fixing part30 fixed to the center of back surface plate 120. Note that touch panel140 is an example of the operation contact surface part, and it is fixedat its back surface side to be in surface-contact with surface-partfixing part 44 of movable part 40. Thereby, touch panel 140 itselfintegrally drives with movable part 40. In touch panel 140, thedirection the operator touches the screen at the time of operations isthe same as the vibrating direction of movable part 40 and movable yoke40A in vibration actuator 110.

As described, with touch panel apparatus 100 on which vibration actuator10 is mounted, touch panel 140 is directly operated, that is, touchpanel 140 together with movable part 40 is driven in the same directionas the finger touching direction. Therefore, touch panel 140 can bedirectly driven with strong vibration.

Thereby, at the time of operations performed by touching an image suchas a mechanical switch displayed on touch panel 140, it is possible tomove movable part 40 to give an operational feeling according to theimage, such as an operational feeling felt when operating an actualmechanical switch, thereby achieving fine operability withcomfortableness.

With in-vehicle products and industrial devices in particular, touchpanel apparatus 100 can be applied to an operation apparatus on whichoperations are inputted by having a finger or the like touch the imageon the screen. In that case, touch panel apparatus 100 is effective as atouch display apparatus and an operation apparatus provided with thetouch panel apparatus that generates vibration in response to a touchoperation of the operator made on the image and returns a sameoperational feeling as the operational feeling at the time of touchingthe image such as the mechanical switch displayed on the screen.

Embodiments of the present invention have been described above. Notethat descriptions above are exemplifications of the preferredembodiments of the present invention, and the scope of the presentinvention is not limited thereto. That is, descriptions of theconfigurations of the apparatuses and shapes of each component areexamples, and it is obvious that various changes and modifications ofthe examples are possible without departing from the scope of thepresent invention.

INDUSTRIAL APPLICABILITY

Even when attached to a touch panel, the vibration actuator according tothe present invention exhibits the effect capable of giving a preferableoperational feeling to the user at the time of operating the touch paneland reducing the thickness. For example, the vibration actuator iseffective when used for moving the touch panel itself in a carnavigation apparatus and the like.

REFERENCE SIGNS LIST

-   10, 10A, 10B, 110 Vibration actuator-   20 Core assembly-   22 Coil-   24 Core-   26 Bobbin-   26 a, 26 b Split body-   28 Fixing hole-   30 Fixing part-   32 Base part-   32 a Attaching part-   32 b Bottom surface part-   33 Fastening hole-   36 Opening part-   40 Movable part-   40A Movable yoke-   41, 41A Yoke-   44 Surface-part fixing part-   44 a Fixing surface-   46, 47, 46A, 47A Attracted surface part-   48 Opening part (Fixing-part side opening part)-   49 Notch-   50, 50-1, 50-2, 450-1, 450-2 Plate-shaped elastic part-   52, 452 Fixing-body side fixing part-   54 Movable-body side fixing part (movable-body side attachment part)-   56, 456 Bellows-like elastic arm part-   62, 64, 68 Screw-   70 Detection sensor-   80 Electrostatic capacitance sensor-   92, 94, 98 Rivet-   100 Touch panel apparatus-   120 Back surface plate-   140 Touch panel-   160 Pillar part-   241 Core main body-   242, 244 Magnetic pole part

What is claimed is:
 1. A vibration actuator, comprising: a fixing partincluding a coil, and a core around which the coil is wound, the coreincluding both ends projecting from the coil; a movable part disposedsuch that the movable part faces the both ends of the core at a positionclose to the both ends of the core with a gap provided between themovable part and the both ends of the core in a vibration directionorthogonal to a winding axis of the coil, the movable part including ayoke formed of a magnetic material, and the movable part being fixableto an operation contact surface part that is operated by contact; and aplate-shaped elastic part fixed between the movable part and the fixingpart, the plate-shaped elastic part including an elastically deformablebellows-shaped part, the plate-shaped elastic part elasticallysupporting the movable part to be movable with respect to the fixingpart in the vibration direction.
 2. The vibration actuator according toclaim 1, wherein a plurality of the plate-shaped elastic parts are fixedat symmetrical positions with respect to a center of the movable part.3. The vibration actuator according to claim 2, wherein the movable partincludes a surface including a trapezoidal shape in a plan view andincluding a plurality of recesses at positions symmetrical with respectto the center, the recesses being defined by a hypotenuse of thetrapezoidal shape, and the plate-shaped elastic part are arranged atpositions symmetrical with respect to the center in the plurality ofrecesses in a plan view.
 4. The vibration actuator according to claim 1,wherein the plate-shaped elastic part connects the movable part and thefixing part together, and includes at least two or more arm parts eachhaving the bellow-shaped part.
 5. The vibration actuator according toclaim 1, wherein the core is formed in an H-type shape and the both endsof the core project in a direction orthogonal to a winding axisdirection of the coil in a portion around which the coil is wound, theboth ends are projected in a direction orthogonal to the winding axisdirection of the coil, and the core includes counter surface partsprovided in parallel to each other with a space interposed therebetween,each of the counter surface parts being provided opposite to the yokevia the gap.
 6. The vibration actuator according to claim 1, wherein:the plate-shaped elastic part is formed of a magnetic material, and amovable-body side attachment part of the plate-shaped elastic part isdisposed in a winding axis direction of the coil or a directionorthogonal to the winding axis direction with respect to each of theboth ends of the core, and forms a magnetic path together with the corewhen the coil is energized.
 7. The vibration actuator according to claim1, wherein the yoke is disposed with the gap provided between the yokeand both ends of the core in the vibration direction, and includes, at aposition opposite to the coil, an opening part to which the coil isinserted.
 8. The vibration actuator according to claim 1, wherein: thefixing part comprises a base part including a fixing-part side openingpart to which a part of the coil is inserted and disposed, and the coreis fixed to the base part in a state where a part of the coil isdisposed inside the fixing-part side opening part.
 9. The vibrationactuator according to claim 1, wherein the plate-shaped elastic part isfixed by a screw or a rivet.
 10. The vibration actuator according toclaim 1, wherein the plate-shaped elastic part includes a strain sensorfor detecting a push-in amount when the plate-shaped elastic part ispushed in.
 11. The vibration actuator according to claim 1, wherein thefixing part includes an electrostatic capacitance sensor for detecting apush-in amount when the plate-shaped elastic part is pushed in, theelectrostatic capacitance sensor being provided opposite to theplate-shaped elastic part.
 12. The vibration actuator according to claim1, wherein the plate-shaped elastic part is a member integrated with theyoke.
 13. A vibration presenting apparatus, comprising: the vibrationactuator according to claim 1; and a touch panel on which the vibrationactuator is mounted.
 14. The vibration actuator according to claim 1,wherein a fixing-body side fixing part of the plate-shaped elastic partis fixed to an upper surface of an attaching part of the fixing part,and a movable-body side fixing part of the plate-shaped elastic part isfixed to the upper surface of the movable part in a laminated state onthe movable part, the movable part being arranged such that a height ofan upper surface of the movable part is equal to or less than a heightof an upper surface of the fixing part at the fixing-body side fixingportion.
 15. The vibration actuator according to claim 1, wherein theplate-shaped elastic part includes a plurality of the bellows-shapedparts having the same height of an upper surface in the vibrationdirection.
 16. The vibration actuator according to claim 1, wherein theplate-shaped elastic part includes a plurality of the bellows-shapedparts formed at different positions in a direction orthogonal to thewinding axis of the coil.